Description

Having spent a good deal of time enjoying the company of their newfound family and friends at Witch Mountain and intensively studying and practicing their supernormal powers, it is decided that Tony and Tia deserve a vacation in Los Angeles, California. Uncle Bené drops them off in their flying saucer in the Rose Bowl Stadium, after which they quickly become separated from each other. Dr. Gannon and Letha happen to see Tony using his powers, kidnap him, and successfully test the doctor's new mind-control technology on him. With Tony at his robotic bidding, Dr. Gannon hopes to achieve recognition within the scientific community and worldwide power, while Letha merely wants a return on her investment.

Tia must find Tony and foil the villains' nefarious plans. Fortunately, a group of wanna-be tough guys called the Earthquake Gang and hapless truant officer Mr. Yokomoto  whom the guys call "Yo-Yo"  come to her aid. The boys and their relationship with "Yo-Yo" bring a great deal of comic relief to the film, along with the underlying message that it might actually be "cool to stay in school."